U.S. Pat. No. 3,016,780, issued Jan. 16, 1962, to D. W. Mosen describes a log accumulator in which a plurality of fingers, which serve as log carriers, are mounted on a pair of sprocket driven endless chains. The fingers have a shallow groove in which the log rests. The accumulator is loaded by means of a conveyor which longitudinally directs the log between adjacent carrier fingers of the accumulator. When the accumulator is indexed in the accumulate direction, the carrier fingers lift the log from the conveyor. The accumulator is unloaded by indexing the accumulator in the discharge direction which causes a log to be placed on the accumulator conveyor. A pneumatically operated pusher plate transversely pushes the log off the conveyor onto a support bar located along side the accumulator.
Another log accumulator is described in U.S. Pat. No. 3,762,582, issued Oct. 2, 1973, to R. E. Barnhart, et al. Barnhart, et al. also describe an accumulator in which the log carriers are supported by a pair of sprocket driven endless chains. End support members of the log carrier are pivotally mounted so that the log carriers always remain in an upright position regardless of the direction of travel of the chain. When a log carrier is at the loading station, it is in axial alignment with in-feed and out-feed conveyors. The log carrier is loaded by the in-feed conveyor, with the assistance of a pusher, which longitudinally directs a log onto the carrier. The accumulator is then indexed in an accumulate direction to store the log. Unloading is accomplished by indexing the accumulator in the discharge direction which causes a log to be placed at the load/unload station. The pusher then longitudinally pushes the log off of the carrier onto the out-feed conveyor.
Accumulators that are loaded and unloaded at the same station, such as those described in the Mosen and Barnhart et al. patents, are generally referred to as last in, first out accumulators because the last roll to be accumulated is the first roll to be discharged. The Mosen and Barnhart et al. accumulators were both loaded by longitudinally directing a log over a carrier. The Barnhart et al. accumulator is discharged by longitudinally directing the log off of the carrier while the Mosen accumulator is discharged by transversely pushing the log off of the carrier.
Another sprocket driven endless chain accumulator is described in U.S. Pat. No. 4,142,626, issued Mar. 6, 1979 to J. J. Bradley. The log carriers are supported by the chains and are pivotally mounted so that the log carriers remain upright as they travel through the accumulator. The carriers are loaded from a rolldown table located along side the accumulator. A butterfly feed mechanism, located between the rolldown table and the carrier to be loaded, transversely drops a log into the carrier. As a loaded log carrier approaches an unloading station, a trip mechanism engages a trip pin mounted on the log carrier which rotates the carrier and causes a log to be transversely unloaded onto a conveyor.
U.S. Pat. No. 4,168,776, issued Sept. 25, 1979 to C. H. W. Hoeboer, also describes a sprocket driven endless chain accumulator in which the carrier members are supported by the chains. Carrier loading is accomplished by means of an inclined, rolldown table that transversely extends into the path of the carriers. Stops at the end of the table position the log over a log carrier. When the accumulator is indexed, the carrier lifts the log off of the table. As a loaded log carrier approaches the unloading station, a cam surface on the carrier cooperating with a pin mounted in the accumulator causes the carrier to rotate thereby transversely directing the log onto a rolldown table.
The accumulators described in the Bradley and Hoeboer patents have separate load and unload stations and are generally referred to as first in, first out accumulators because the first log into the accumulator must travel to the unload station in order to be discharged. In the accumulators described by Bradley and Hoeboer, the logs are transversely loaded into the carriers and are transversely unloaded by rotating the carriers at the unload station.